Beam splitters for coherent light beams, usually beams generated by lasers, have been used in a variety of applications, including holographic cameras and interferometers. The beam splitters known in the art have generally been unduly complex and expensive, particularly for applications demanding a truly broad ratio of intensities for the split beams, e.g. a full range of zero to 100% of input light to either output beam. Moreover, known beam splitters have usually been susceptible to major errors when subjected to virtually any vibration or like disturbance occurring during operation.